refactor(checkhealth)!: rename to vim.health, move logic to Lua #18720

- Complete function:
  There was lots of unnecessary C code for the complete function, therefore
  moving it to Lua and use all the plumbing we have in place to retrieve the
  results.
- Moving the module:
  It's important we keep nvim lua modules name spaced, avoids conflict with
  plugins, luarocks, etc.

runtime/lua/vim/_editor.lua

@@ -49,6 +49,7 @@ for k, v in pairs({
   diagnostic = true,
   keymap = true,
   ui = true,
+  health = true,
 }) do
   vim._submodules[k] = v
 end